[linux-audio-user] still have bad sound

Dave Phillips dlphilp at bright.net
Fri Feb 13 09:01:39 EST 2004


Greetings:

  Thank you to all who replied with suggestions for resolving my sound 
problem. After working all last night on it I've come to some new 
possible conclusions.

  First, sound is fine outside of X. I tested realtime output from three 
long Csound compositions (Face On Mars, Incantations, and Trapped In 
Convert), they all played fine, even when I moved the console mouse.

  Second, sound is fine in X with *some* applications. XMMS plays things 
perfectly, no glitches while I move the mouse or switch workspaces. The 
major offender has been Csound when I run an app (ImproSculpt) utilizing 
the FLTK opcodes. The audio distortion had become intolerable, making 
the app nearly useless. Btw, the distortion wasn't just from the mouse, 
it was bad even without mouse movement, full of pops and crackles. The 
mouse really zippered when I moved it across the display, and moving 
windows chopped things up more.

  Following advice found in an article by Daniel Robbins 
(http://www-106.ibm.com/developerworks/library/l-hw2.html) I adjusted 
the PCI latency timer (with setpci) for my sound card. At last I 
eliminated *most* of the trouble with ImproSculpt. The mouse still zips 
but the overall distortion is gone. I thought that perhaps FLTK had been 
compiled with GL dependencies, but 'ldd lbfltk.so' showed none.

  I do have the no-hlt option appended to lilo.conf, but I think that 
the nVidia driver's DRI overrides the option. Bummer. So I'm still 
trying to eliminate the mouse zip in ImproSculpt, but overall sound is 
much improved.

  Btw, here's what I have in lilo.conf, I presume I have the syntax 
correct :

    append="hdc=ide-scsi no-hlt root=LABEL=/"

  Lilo doesn't complain about it, so I figure it's right, but maybe not... ?

  Back to the hack...

Best,

dp





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